In order to receive positioning information and positioning augmentation information that are broadcast from various positioning satellites such as a quasi-zenith satellite of Japan and a GPS (Global Positioning System) satellite of the United States, it is essential that a satellite is visible. Conventionally, positioning using information from a positioning satellite cannot be performed in the indoors where the satellite is not visible. Further, it is also difficult to use a positioning satellite in a boundary area in moving from the indoors to the outdoors or from the outdoors to the indoors due to the effect of a roadside tree, the effect of multipath and the like on a signal from the positioning satellite, and also because it takes time to re-acquire the signal.
Further, various schemes of positioning techniques in the outdoors or positioning techniques in the indoors have been proposed, and commercialization of some of the schemes is being promoted (for example, see Patent Literature 1).
In an independent positioning scheme in which a positioning device independently determines a position by using code information of a GNSS signal from a satellite positioning system (GNSS: Global Navigation System) such as a GPS, GALILEO, GLONASS, or quasi-zenith satellite system, an error included in the GNSS signal results in positioning accuracy on the order of meters.
Compared to the independent positioning scheme, a positioning scheme using augmentation information realizes high accuracy positioning on the order of centimeters.
This positioning scheme uses observed data at an electronic reference point or the like, the accurate coordinates of which are known, to estimate an error arising from a positioning satellite and an error arising from an atmospheric state for each positioning satellite and provide an amount of error correction as the augmentation information to a positioning device.
The augmentation information is transmitted from a quasi-zenith satellite or a wireless LAN (Local Area Network) network, for example, to be provided to the positioning device.
The positioning device performs error correction on a positioning signal by using the amount of error correction in the augmentation information to thus be able to realize high accuracy positioning on the order of centimeters.
A technique disclosed in Patent Literature 2 relates to the high accuracy positioning using the augmentation information, for example.